We utilize semantic versioning as defined here:

http://semver.org/

A short summary:

"Given a version number MAJOR.MINOR.PATCH, increment the:

1. MAJOR version when you make incompatible API changes,
2. MINOR version when you add functionality in a backwards-compatible manner, and
3. PATCH version when you make backwards-compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format."

When in doubt, we will prefer creating a new minor release over creating a patch to an existing minor release.  Working on multiple parallel branches of releases splits our capacity, and reduces our effectiveness as a community.